Scientists in Australia have found evidence the continent was once attached to Canada.
They found rocks in northern Queensland which bear striking similarities to those found in North America, Curtin University said in a statement.
The rocks were uncovered in Georgetown, 412km west of Cairns.
"Our research shows that about 1.7 billion years ago, Georgetown rocks were deposited into a shallow sea when the region was part of North America," said PhD student Adam Nordsvan.
"Georgetown then broke away from North America and collided with the Mount Isa region of northern Australia around 100 million years later."
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When North America and Australia were one, they weren't alone - making up part of supercontinent Nuna, a billion years before the formation of the dinosaur-era supercontinent Pangaea.
"The team was able to determine this by using both new sedimentological field data and new and existing geochronological data from both Georgetown and Mount Isa to reveal this unexpected information on the Australia continent," said Mr Nordsvan.
Australia's not exactly known for its mountains, so it seems the collision between the Georgetown and Mt Isa regions was very slow, by geological standards - in contrast to the Himalayas, created when India collided with Asia.
"This new finding is a key step in understanding how Earth's first supercontinent Nuna may have formed, a subject still being pursued by our multidisciplinary team here at Curtin University."
The research was published on Friday in journal Geology.
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